Much remains to be elucidated concerning the effect of marijuana and its derivatives or metabolites on intraocular pressure. Studies will be made of the effect of these compounds on the secretion and filtration rates across the isolated ciliary epithelium to determine the membrane effects of the drugs. Whole animal studies on the living eye will be made to measure the drug effects on intraocular pressure, total outflow facility, pseudofacility, capillary pressure, secretion, ultrafiltration, blood and penetration of the drugs, using radioactive compounds, when administered topically or systemically. Dose response curves for many parameters will be established using many of the active compounds. Determinations of the pharmacology of marijuana will be made in order to identify the site and mode of action of the drug in the eye.